(1) Field of the Invention
The present invention relates to an applicator for cosmetics and medical use, which includes a container for applying a liquid and is required to uniformly apply a liquid of a relatively high viscosity and the like.
(2) Description of the Prior Art
Conventionally, there have been diverse proposals of applicators for applying liquid content solutions.
For example, there have been applicators that simply apply and spread a liquid with a cotton swab or sponge, and applicators that deliver a liquid and spread the liquid by its applying part of the container, disclosed in Japanese Patent Application Laid-open 2010-42046 (:Patent Document 1) and Japanese Patent Application Laid-open 2007-130157 (:Patent Document 2).
Usually, in liquid application the applicator is demanded to spread the liquid thinly and uniformly on the applied surface.
Though use of the fingers for application facilitates the liquid to spread uniformly, there is the problem that the fingers dirty.
Use of cotton swabs makes application work easy, but entails problems of uneven application and adhesion of fibers.
When sponge is used as the applying part, the liquid permeates over the sponge surface and is likely to produce spoils on the applied surface, causing hygienic problems. Further, there is also another problem that the component easy to permeate into sponge, such as a solvent of the liquid, is soaked into the sponge, changing the composition of the liquid retained in the applying part.
There have been also various kinds of applicators using brushes as their application body. A brush is an application body (applying part) formed of a bundle of fibers, hence it leaves fiber traces on the applied surface upon application, hence makes it difficult to apply the liquid thinly and uniformly.
In the applicator formed of silicone as proposed by Patent Document 1 of a liquid applicator, though the application body will not absorb the liquid the application body has approximately uniform elasticity because the application body is a silicone molding. Accordingly, when the application body having a substantially spherical surface is pressed against the applied surface, the pressure becomes higher at the center of the contact area on the sphere than in the surrounding of the center so that the liquid is not applied uniformly but is distributed thinner at the center the contact area and its vicinity than in the surrounding thereof. As a result, when the liquid is applied by moving the application body under this condition, the liquid after application will not become uniform but thin application of the liquid will appear along the trance of the center and its vicinity.
Further, when the applicator is of a flat application body, it is possible to apply uniform pressure if liquid application is performed on the surface of a perfect flat object. However, even in this case, if the application body is slightly inclined, or if the surface to be applied is not a perfect plane, the pressure becomes uneven so that the resultant thickness of the application liquid becomes uneven.
When a liquid delivery hole is formed in the application body as in Patent Document 1, the applied liquid is scraped by the edge forming and surrounding the hole as the applicator moves. As a result, the scraped trace is liable to appear on the liquid surface along the trace of the delivery hole.
In particular, a noticeable amount of liquid is scraped by the edge having the configuration shown in FIG. 6 of Patent Document 1.
When the applicator has an elastic spatula-like application body that can overall deform in conformity with the surface to be applied on as disclosed in Patent Document 2, the variation of the pressure of the application body across the width direction can be suppressed thanks to deformation of the application body following the applied portion. However, the pressing force from the applicator depending on elapsing time cannot be made uniform, so that the application thickness becomes uneven with respect to the direction of liquid application.
Further, this configuration also entails the problem that when a delivery hole is formed in the application body, the liquid is scraped by the edge forming and surrounding the hole so that no uniform application surface can be obtained.